It is accessible only by a cart operated by one of the bank's goblin employees, and by using a small gold key.

In 1991, Harry Potter was escorted to Gringotts by Rubeus Hagrid, and learned that his late parents had left him a small fortune in their vault, of which his guardians knew nothing. This was very fortunate for Harry, since they would have surely taken most, if not all, as "proper compensation" for "opening their home" to him.[1]